Process of concentrating nitrosulfuric waste acid.



No- 898,390. PATENTBD SEPT. 8, 1903 v H; PAULING.

moonss or GONGENTRATING mmos'nmmmc WASTE A0111,

APPLICATION FILED JULY 29,1907.

e722 van for.

UNITED STATES PATENT OFFICE,

HARRY PAULING, OF GELSENKIRCHEN, GERMANY, ASSIGNOR TO THE FIRM OFSALPFTEPu SAURE INDUSTRIE-GESELLSGHAFT, G. M. B. H., OF GELSENKIRCHEN,GERMANY.

PROCESS OF CONCENTRATING NITROSULFURIC WASTE ACID.

Specification of Letters Patent.

Patented Sept. 8, 1908.

ori inal application filed August 1a, 1908, Serial No. 830,387. Dividedand this application filed July 29, 1907.

, Serial m. 386,072.

To all whom it may concern:

Be it known that I, HARRY PAULING, a subject of the German Emperor, andresident of 84 Wilhelmstrasse, in Gelsenkirchen IV, in the Province ofWestphalia, Kingdom of Prussia, Germany, have invented certain new anduseful Improvements in Processes of Concentrating Nltrosuliuric WasteAcid,

of which the following is a specification.

There is a sort of waste acid resulting in the manufacture of explosivesubstances and like processes connected. with nitritications, such wasteacid consisting of a mixture of diluted sulfuric acid with dilutednitric acid. This waste acid is the remainder of the socallednitrosulfuric acid used in leiiecting the said nitrit'ying processes,the acid being at the beginning of such operations concentrated, butsuffering a loss in nitric acid while at the, same time it receives anaddition of water. i

The present invention consists in a process that shall enable a readyconcentration or regeneration of the diluted nitric acid contained insuch waste acid, so as to render it reusable for nitrifications or thelike.

To such end the waste acid is electrolyzed in company with dilutednitric acid, in a pcculiar manner, as will be understood from thefollowing description and be particularly pointed out in the appendedclaim, refcrence being had to the accompanying drawing which is adiagrammatical view of an apparatus'adapted for eil'ecting my process.

The apparatus represented consists, in substance, of a U-tube a, b, across tube e establishing communication between the two legs thereof,and in such a manner that one end of this tube extends into the interiorof the leg (1', as shown; a feed tube f, and drain cocks g and c is theanode and d the cathode.

The operation of this device is as follows: The waste acid is filledinto the leg a so as to surround the anode, while the leg b is sup--plied with diluted nitric acid, which will thus be in contact with thecathode. Hereu on an electric current is passed through the iquid, withthe result that at the anode c oxygen is formed, while at the cathode dnitric oxids are generated. The latter pass through the tube e into theleg 0, where they dissolve in the diluted nitric acid surrounding theanode, so as to be converted into nitric acid by the action of theoxygen set free at the anode. After a suitable or desired degree ofconcentration has been obtained in the lega the diluted nitric acidcontained in the le 11 is dischar ed through a cock 7c. This 8.01(l,,

trolyzing such liquid, and conducting'the nitrogen oxids liberated atthe cathode into the anode chamber.

In witness whereof I have hereunto signed my name this 22 day of June1907, in the presence of two subscribing Witnesses.

' HARRY PAULING.

Witnesses CARL HEINRICH,' RICHARD STERKEL.

